Ultrasonic guided waves applications for locating and quantifying pipelines defects

On-line Health Monitoring of industrial structures in particular the oil and gas transporting system such as pipelines is of great importance to the reliability and survivability of the plant. In this research the propagation of Ultrasonic Guided Waves as a tool to condition monitoring of the pipes was investigated. Also, under this research the Kirchhoff flaw approximation model was modified to provide an estimation of the size and location of flaws that may exist along the pipe. The modified model and the dispersion curves generated by the Ultrasonic Waves using PCDISP software can provide assessment of the location and extent of the flaw. Several simulation trials were performed using Matlab to validate the feasibility and applicability of the modified model and the results indicate that this model can accurately estimate the size and location of the flaws that exist in the pipe

Probabilistic methods for assessing the performance of offshore pipelines condition monitoring systems

Oil and gas condition monitoring systems play a major role in maintaining the operability, integrity, and reliability of oil and gas infrastructure. A leak detection monitoring system (LDS) constitutes an important member of these systems. The main function of this system is to detect the occurrence and location of hydrocarbon leakages in a timely manner before the leaked products can cause a devastating effect on production, health, safety, and the environment. To ensure the continuity of operation and the safety of personnel as well as the environment, this system should be assessed on a regular basis. Traditionally, a deterministic approach is adopted to assess such systems. A deterministic assessment does not consider uncertainties or random variabilities that are inherent in the performance parameters. Thus, it produces results that may not characterize the actual situation of the system or its circumstances. To tackle this issue, it is proposed to use a probabilistic approach to assess the performance since it allows the incorporation of any uncertainties or random variabilities that may exist in the assessment. Hence, a quantifiable probability of failure can be estimated. Once the probability and consequences of failure become known, risk can be easily estimated. A complete assessment of risk cannot by obtained without incorporating the probability of failure of the pipeline itself. The major research activities include, formulation of the LDS probability of detection and false detection for a single point along the oil and gas transport component; development of a probabilistic performance assessment scheme for the entire LDS along the oil and gas transport component using a limit-state approach; application of probabilistic methods to determine the probability of failure and the remaining life of the oil and gas transport component and development of a risk-based assessment methodology to determine the risk associated with the simultaneous failure of the LDS and the oil and gas transport component (i.e., pipelines). These major research components establish the foundation for an overall evaluation scheme that can be used to provide an up-to-date assessment of the oil and gas transport components and the LDS. The outcome of the assessment can serve as a basis for a well-informed decision-making process that enables the decision makers to determine the best strategy for assessing and maintaining the integrity of the evaluated systems